A Voice over Long Term Evolution (Voice over Long Term Evolution, VoLTE) solution is an Internet protocol (Internet Protocol, IP for short) data transmission technology. An LTE system may implement a data service and a voice service by using the technology. To be specific, a same network may be used for the voice service and the data service, thereby improving call quality of the voice service.
Currently, during a VoLTE voice call, when calling UE calls called UE by using a core network device, the called UE needs to complete mobile terminated (Mobile Terminated, MT for short) signaling interaction with the core network device. The called UE rings only after the called UE and the core network device complete the MT signaling interaction.
However, in the prior art, the called UE does not ring if the MT signaling interaction between the called UE and the core network device fails, resulting in that a called user cannot notice a current incoming call of the calling UE, and man-machine interaction is not intelligent enough.